bug in create table with serial

In PostgreSQL 7.3b2, if I create a table like so:

create table customers (id serial primary key);

The id field will be created of type 32 bit integer, yet the upper limit
for the sequence will be relative to a 64 bit integer.

\d customers
Table "public.customers"
Column | Type | Modifiers
-------------+--------------+-----------------------------------------------------------
id | integer | not null default
nextval('public.customers_id_seq'::text)

shop-devel=# select * from customers_id_seq;
-[ RECORD 1 ]-+--------------------
sequence_name | customers_id_seq
last_value | 1
increment_by | 1
max_value | 9223372036854775807
min_value | 1
cache_value | 1
log_cnt | 1
is_cycled | f
is_called | f

shop-devel=# select version ();
version
---------------------------------------------------------------------
PostgreSQL 7.3b2 on i386-portbld-freebsd4.7, compiled by GCC 2.95.4